The use of light emitting diodes (“LED”) in lighting fixtures to supply the desired illumination is becoming more prevalent. However, the voltage necessary to power an LED circuit board for use in lighting fixtures oftentimes renders the board a non-Class 2 component as defined by the National Electric Code (“NEC”). See NEC (specifically Section 725 and Table 11(B)) (2005), the entirety of which is herein incorporated by reference. Existing LED circuit boards which operate beyond the limits of Class 2 power are designated by UL as a “risk of fire” and must be contained. See UL 8750 (specifically section 3.17)(2008), the entirety of which is herein incorporated by reference. Containment requires that the LED board be enclosed so that a person cannot easily come into contact with the board. More specifically, the enclosure must be manufactured from a 5VA compliant material (one that passes stringent flammability testing pursuant to UL 94, the entirety of which is herein incorporated by reference) and the board must not be easily accessible. See UL 8750, Table 9.1. For example, the enclosure cannot be removed easily so as to gain access to the board. Rather, it should be sufficiently secured so that tools are required for its removal.
Enclosures have traditionally taken the form of a glass refractor that is secured in a lighting fixture a distance from the LED board. The refractor thereby prevents easy access to the LED board within the fixture. However, refractors are traditionally made of glass, which, while 5VA compliant, can be prone to break and thereby present additional risks to handlers. Moreover, because the light emitted from the LEDs in such fixtures must pass through the glass refractor, some of the light is lost, thereby impacting the efficiency and effectiveness of the fixture. While metal is also a 5VA compliant material, use of it in the fixture elevates the risk of electric shock and, given that it is nontransparent, impedes the transmission of the light emitted from the LEDs. Given the difficulty in designing a enclosure that satisfies the 5VA flammability rating without introducing other potential safety hazards, lighting fixture manufacturers have typically resorted to use of less hazardous Class 2 or Class 3 power sources. In this way, overall lighting system efficiency is sacrificed to avoid the need to comply with the strict requirements promulgated by the UL and NEC.